Reactivity change of IgE to buckwheat protein treated with high‐pressure and enzymatic hydrolysis

BACKGROUND Buckwheat is a popular food material in eastern Asian countries that can cause allergenic response. This study was conducted to evaluate the effects of hydrolysis with papain and high‐pressure ( HP ) treatment of buckwheat protein ( BWP ) on reactivity of immunoglobulin E ( IgE ) and its secondary structure. RESULTS Reactivity of IgE was examined by enzyme‐linked immunosorbent assay ( ELISA ) with serum samples from 16 patients allergic to buckwheat. Reactivity of IgE to hydrolysate of BWP with papain showed a maximum decrease of 79.8%. After HP treatment at 600 MPa for 1 min, reactivity of IgE to BWP decreased by up to 55.1%. When extracted, BWP was hydrolyzed with papain overnight following HP treatment at 600 MPa which the reactivity of IgE decreased significantly by up to 87.1%. Significant changes in secondary structure of BWP were observed by circular dichroism ( CD ) analysis after hydrolysis with papain following HP treatment. CONCLUSION Reduction of reactivity of IgE showed a correlation with changes in secondary structure of BWP , which may cause changes in conformational epitopes. This suggests the possibility of decreasing the reactivity of IgE to BWP using combined physical and enzymatic treatments. © 2015 Society of Chemical Industry